Apparatus for amalgamating



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J. L. STEWART.

APPARATUS FOR AMALGAMATING. No. 262,628. Patented Aug. 15,

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UNITED STATES PATENT OFFICE.

JOHN L. STEWART, OF PHILADELPHIA, PENNSYLVANIA.

4APPARATUS FOR AMALGAMATING.

SPECIFICATION forming part of Letters Patent No. 262,628, dated August15, 1882,v

Application filed December 24, 1881.

To all whom it may concern:

Be it known that I, JOHN L. STEWART, of

the city of Philadelphia, in the State of Pennsylvania, have invented anImprovement in the Apparatus for Amalgamating Precious Metals, of whichthe following is a specification.

The object of my invention is to provide means whereby precious metalscontained in ore may be brought into more intimate and thorough contactwith the amalgamating-bath than has heretofore been possible, withtheresult that the process of amalgamation may be more rapidly, cheaply,and eliiciently carried on than by the processes heretofore in use.

My invention consists as hereinafter described aud claimed.

In the drawings, Figure l is a vertical central sectional view of anapparatus conveniently embodying my invention. Fig. 2 is a plan view ofsaid apparatus, partially sectional to illustrate construction.

Similar letters of reference indicate correspondin g parts.

A is an iron pot or vessel, havinga concave bottom, and supported uponbrick-work X.

B is a cylindrical vessel located Within the vessel A, attached to andsuspended from the top thereof, and provided with a lower cupshaped orexpanding and Haring end,W,which forms a false-bottom to the vessel A.This false bottom Wis located some distance above the bottom oftheexterior vessel, A, so as to leave a space between it and the bottom ofsaid exterior vessel, with the result that material forced from theAlower end of the vessel B into the vessel A- is brought into closecontact with the heated bottom of the last-named vessel. The falsebottom is on its under side provided with radially-extending ribs a a.a, which serve to form channelsor outlets from the vessel B to theexterior vessel, A.

P is a pipe through which ore'" is fed to the vessel B.

F F are pipes leading outwardly from the vessel B and downwardly towardthe false bottom of the vessel A.

C is a shaft concentric within the vessel B, provided with helical orpropeller blades D D at a point ilush with or below the lower edge ofthe openings into the pipes F F. This shaft (No model.)

rests in and upon a bearing, E, upon the bottom of the vessel A, whichbearing is formed with ports or outlets at its lower end, that sand orother extraneous matter may escape if under any circumstances it shouldfind its way therein. The upper portion of the shaft revolves within abearing, S, which may be at tached to a bracket or other suitablesupport. The upper extremity ofthe shaft plays Within an abuttingbearing, which prevents the propellers from forcing the shalt upward andout of proper adjustment. This shaft may bedriven by gearing Q B, of theusual construction.

The pipes F F are provided with valves G G, adapted to be operated byvalve-stems H H, or by any suitable means.

Lis apipe or conduit connected with and leading from the true bottom ot'the vessel A, by which the liquid contents of said vessel may be drawnott, and through thepipeNdischarged into any suitable receptacle.

B3 is a gangue or dbris escape or overfiow pipe, and O is a dbris organgue outlet pipe, extending outwardly and downwardly from the upperportion of the vesselA, and provided with an injection-pipe, B2, havinga rose,by which water may be mixed with the escaping gangue or dbris forthe purpose of preparing the same for wet concentration should thelatter process be found necessary.

B' is a steam feed-pipe opening into the upper portion of the vessel A.

K is a lloat or indicator to determine the height of the duid masswithin the vessel A. Y is a furnace, and Z grate-bars thereof.

l do not confine myself to the exact construction and detail of partsshown and described, as it is obvious that the same may be departed fromwithout changing the character of my apparatus or modifying myinvention.

Having thus described a convenient form of apparatus, its operation isas follows: The vessel A is lled with molten lead, mercury, or otheramalgamating material to a point somewhat above the level of the upperedge of the openings of the pipes F F from the vessel B, within whichlatter vessel the material finds its level. When molten lead is employedas the amalgamating bath sucient heat is supplied and maintained, bymeans of a re in the furnace Y or by means of any suitable hot-air orsuperheated-steam heating device, to amalgamate the precious metalscontained in the ore to be treated after the latter has beenbrought intocontact therewith in the vessels A and B. The propellers D D are thenoperated at sufcient speed to force or propel the amalgamating-liquid inthe interior chamber, B, downwardly through the same and outwardlybetween the ribs a aiuto the chamber A until thelevel of theamalgamating-bath in the vessel B is below the level ofthe lower edgesof the respective openings into the pipes F F. The valves G Gr are thenopened sufficiently to permit the proper quantity of amalgamating-liquidto iiow from the vessel A back into the vessel B of its own gravityinorder to obtain the desired rapidity of circulation of the liquid fromthe vessel A through the tubes F F and cylinder B. Ore containing theprecious metals which has been previously prepared for dry amalgamationis now fed through the tube P in proper quantities to theamalgainating-chamber B, Whereit is brought into contact with thepropellers D D and with the molten lead or other amalgamatingbath, andwhere it is retained for a longer or shorter time, at the pleasure ofthe operator.

By proper adjustment of the valves Gr G a greater or less quantity ofmaterial may be permitted to flow through the pipes F F into the ani algam atin g-chamber B.

It will be observed that the circulation of the liquid and the length oftime that the ore is subjected to the action of the propellers and themolten material are both under the complete control of the operator. Theore, being of much less specific gravity than the molten lead, will,when immersed therein, tend to rise rapidly to the surface, and as thepropeller is set vertically in the chamber B, the ore being forcedthrough the lead will be continually rising and being pressed againstthe blades of the screw-propeller, by which it will be subjected to agrinding process between the molten lead and said blades. Thepropellers, be-

ing rapidly revolved, cause a thorough incorporation of every particleof the precious metals with the amalgamatingbath. The faces of thepropeller-blades may be provided with ribs or rough projections, so asto increase their agitating and grinding action. It will thus be seenthat the ore and molten lead, upon being admitted to theamalgamating-chamber B, are subjected to a thorough incorporation, andare then forced down through the chamber B into and through thesuperheated channels between the bottom of the vessel A and the undersurface of the false bottom W into the vessel A,where the gangue ordbris rises and flows out through the pipe O by reason of the differencein gravity between the lead and said debris.

The debris may be forced out of the vessel A, it' necessary, by means ofan air or steam -jet admitted to the said vessel through the pipe B',and be conducted through the pipe O to a concentrator, or to thewaste-pile, as may be deemed proper.

In case of scarcityof water for supplying the water-feed B2 the gangueor dbris may be allowed to overflow and escape from the vessel A throughthe overlow-pipes B3.

When quicksilver is employed as the amalgamating-bath the ore may beeither wet or dry, and the quicksilver may be used cold, or it may beheated if the temperature is kept below the point of distillation.

Having thus described my invention, l claiin- In a device foramalgamating precious metals, an exterior pot or vessel, in combinationwith the interior cylinder, B, provided with an outwardly and upwardlyflaring end or Bange, W, located above the bottom of said exteriorvessel, and having openings and valves for controlling said openings forthe return of the amalgam bath to said cylinder, as described, and forthe purpose speciiied.

In testimony whereofl Ihave hereunto signed 9 my name this 20th dayofDecember, A. D, 1881.

JOHN L. STEWART.

In presence of J. BoNsALL TAYLOR, W. G. STRAWBRIDGE.

